Improvement in blast-furnace boiler-ovens



v H. HARRISr Blast-Furnace.Buile`r#0vens.

910.158,209. l vPatented'Dem-2 9;18.74,

Imm@ Fifi Wvvwa'ssa mismo@ THE GRAPHIC CAPFDYD-LITHSJ. 4| PARK PLACE,NA\*.

UNITED STATES PATENT Erre.

HORACE HARRIS, OF TROY, NEW YORK.

' IMPROVEMENT IN BLAST-FURNACE BOlLER-OVENS.

Specification forming part of Letters Patent No. 158,209, dated December 29, 1874 application filed August 18, 1874.

To all whom it may concern:

Be it known that I, HORACE HAEnrs, of the city of Troy, in the county of Rensselaer and State of New York, have invented certain new and useful Improvements in Blast-Fur- Vnace Boiler-Ovens, which are described in the following specification, reference being had to the accompanying drawings, in Which- Figure 1 is a horizontal section of a blastfurnace boiler-oven in which is embodied my invention, taken through the line w x, and showing a plan view of the door of the same. Fig. 2 is a transverse section of the sam e, taken through the line y y; and Fig. 3 is a transverse section through the line z z, Fig. 1. Fig. 4 is a longitudinal vertical section through the line 'c c, Figs. l and 3.

My invention relates to the introduction of highly-heated air into the boiler-ovens of blastfurnaces for the purpose of more perfectly and completely supporting the combustion ot' the gases passing into and through such oven from the furnace in which the crude ore is reduced to cast-iron.

Heretofore blast-furnace boiler-ovens have received air through side openings or doors, such air entering at or about the temperature of the surrounding atmosphere, and the consequence has been that when too little air has been thus admitted the gases have passed oiil only partially and imperfectly consumed; and when these openings or doors have been too widely opened, so as to admit more air than was necessary to fully sustain the combustion of the gas, the result has been Very similar to that of opening the door of the fire-box of an ordinary steam-boiler-i. e., the comparatively cool air undoing the work of the burning gas by coming in contact with and reducing the heat of the boilers, and absorbing or deadening the heat of the gas-dame.

It is a fact Well known among the practical manufacturers of cast-iron from the ore in the blast-furnace that the heat derived heretofore from the combustion of the gases in the boileroven from the blast-furnace alone, supported by the admission of cold air thereto, has been insufficient for the purpose of generating steam enough to satisfactorily operate the engine (especially high-pressure) employed in forcing the blast into the furnace without frequently using extra fuel; and in order to obviate, in a degree, the burning of this extra fuel in the boiler-oven, some manufacturers of pig-iron in blast-furnaces have been obliged to change, at considerable cost and expense, their engines from non-condensing to condensing engines, and even have provided auxiliary boilers in which coal is consumed, in order to insure a steady and constant blast of the required force into the furnace at all times and under all circumstances. In fact, I know of instances in what is known as sixty-feet working blastfurnaces,77 (in which the combustion of the gas in the boiler-oven is supported by cold air,) in order to enable them to perform their work to their fullest capacity and in good working or.V der, it is necessary to consume from thirty to sixty tons of coal extra per week in the production of the requisite amount of steam, and which consumption of extra fuel I obviate by means of my invention.

Myinvention consists in combining, with the combustion-chamber of a blast-furnace boileroven, an air-Hue which makes one or more returns in its traverse through said chamber, a damper governing the supply of air to the iiue, and a perforated bridge-wall to deliver the heated air to the chamber, Aall as hereinafter fully set forth.

In the drawin g, A represents the boiler-oven, which is supplied with gas from Vthe furnace through the pipes or conduits B. The iiues or passages C, in which the air to support the combustion of the gases as they pass into and through the oven A, is heated to a high temperature. The flue or flues C may be constructed in the mason-work in any part of the side or end walls of the oven, or, as shown in the drawing, in the oven-bottom; or these lines may be constructed of pipes, and laid upon the oven-bottom, or arranged in any other part of the oven; but the construction and arrangeof the air passages or fines in or about the oven should be in such a manner and. position that the air in passing through such passages or fiues will become the most highly heated, and, at the same time, will enable the gases to communicate the greatest amount of heat to the boilers D, supported in the oven A. With this object in View, I prefer, when practicable, to construct and arrange the air-passages or t the oven A is absorbed and carried ofi", at the same time accomplishing the result sought to be attained. i'

E represents the dampers or doors for regu- 'latingt-he supply of air into the oven A through the ilues O. These dampers, or their equivalent, may be so arranged, when desired, as to be operated from the en ginefroom by means of a cord or chain communicating therewith. At the outlet of the flue or fines C into the oven A I construct and arrange one or more peri'orated pipes, hoods, or bridge-walls, F, or their equivalent, in such a manner as to cause the heated air to issue from the flue or iiues C into theoven A in jets, and to mix evenly and thoroughly with the gases entering the oven A from the conduits B, to be consumed under and about the boilers D.

By means ofmy invention I have found, by actual experiment, that the heating capacity ofthe oven A is augmented to such an extent that, instead of being obliged to consume extra fuel to enable the boilers to furnish sufficient steam for the purpose hereinbefore mentioned, the said boilers produce more than enough steam for such purpose, so that it is often necessary to check the draft of air into the oven.

Another advantage of my invention is that the accidents that sometimes occursuch as violent explosions in the ovens, in which the side doors, and, at times, the side walls, of the boiler-oven are blown out-are, I have reason to believe, avoided by means of my herein-described invention.

' The fire chamber or chambers G in a boileroven of a blast-furnace in which my invention is embodied land employed are seldom, if at any time, required to be supplied with fuel, only when newly starting up the blast-furnace, and until such furnace gets into full operation, when the grate-bars g can be removed or covered over with ashes, tile, or other non-conductor of heat, and the heat in the oven A is maintained constantly thereafter, by the consumption of the gases from the blastfurnace alone, in the manner and by the means hereinabove described as my invention.

I am aware that it has been heretofore proposed to heat the air required for supporting combustion in gas-furnaces of various descriptions, and also that the supply of air thereto has been regulated by valves and delivered to the furnace through a series of small openings; but the various devices employed for this purpose differ from mine. Neither have they been combined in similar relation. I do not, therefore, broadlyV claim either an airheating iiue or a perforated bridge-Wall.

I claim as my invention- The combination, with a blast-furnace boileroven, of an air-ilue which makes one or more returns in its traverse through the oven, a damper to regulate the supply of air to the flue, and a perforated bridge-wall, through which the heated air from the ue is delivered to the combustion-chamber of the oven, these members being arranged for joint operation, substantially as set forth. v

In testimony whereof I hereunto subscribe my name this 13th day of August, 1874.

HORACE HARRIS.

Witnesses:

J. T. GoonFELLoW, J oHN KNowLsoN, J r. 

